Magnetron sputter coating sources are sources employing crossed electric and magnetic fields over the sputtering surface of the sputter target in an arrangement which traps electrons to create a plasma in a partial vacuum of a gas in a vacuum chamber. The electrons bombard the gas atoms to form positively charged gas ions. The positively charged ions are attracted by a negatively charged target to sputter off particles of the target.
In early magnetron sputter coating systems, it was customary to move the substrates in various ways during coating in order to obtain uniform coating thickness across the substrate and to obtain good step coverage. More recently apparatus has been developed for in situ coating wherein the substrate is held stationary during coating.
Also, there is a growing need for coating larger and larger substrates, and substrates of different shapes. This invention addresses means for filling these needs.
Further, it has been noted that the deposition rate changes as the target becomes eroded. A solution to this problem has been to change the power delivered to the target during sputtering operaton of target, as set forth in the commonly assigned U.S. Pat. No. 4,166,783 entitled "Deposition Rate Regulation by Computer Control of Sputtering Systems". Another power supply control system is set forth in the commonly assigned copending U.S. patent application of Donald R. Boys and Robert M. Smith, Ser. No. 06/564,776, filed Dec. 27, 1983 (U.S. Pat. No. 4,500,408) and incorporated herein by reference. Said pending application also recognizes that the strength of the magnetic field has an effect on the sputter process, and employs an electromagnet for generating the magnetic field so that the strength of such field is controllable.